A satisfactory dentifrice should have a cosmetic effect on teeth, keeping them light colored. It should also have a functional effect on the teeth and mouth, keeping them clean and free from food debris, thereby aiding prevention of tooth decay and promoting gingival health. In order to achieve these objectives, it is necessary to brush with a dentifrice containing an abrasive. The purpose of the abrasive is to aid in removal of the tightly adherent film which, in many persons, contains pigments which color it brown or yellow. The abrasive should remove this film, called the pellicle film, with a minimum abrasion of the underlying tooth material. Enamel, which covers much of the exposed tooth surface, is relatively hard and is not of as much concern as the softer dentin which may be exposed by receding gums.
Beyond the function of a dentifrice in maintaining oral cleanliness, there is merit in including an agent which acts specifically to reduce tooth decay or counteract diseases affecting the gingiva. Work stimulated by the discovery of the beneficial effect of fluoride in drinking water or topically applied to the teeth has led to the development of dentifrices containing water-soluble fluorides. The effect of stannous fluoride in a properly formulated dentifrice in reducing caries has been well established. Other inorganic fluorides such as indium fluoride have also been shown to be effective anticaries agents. It has also been found that bis-biguanide compounds such as those disclosed in U.S. Pat. No. 2,684,924, Rose et al., July 27, 1954, are effective antiplaque agents which demonstrate anticaries activity.
A problem recognized in the scientific and patent literature is that of formulating a dentifrice in which the ionic therapeuutic agents will remain available for treatment of the teeth and not react with the abrasive.
It is an object of this invention to provide an abrasive coated with a water-soluble cationic polymer which improves the compatibility of the abrasive with cationic therapeutic agents, thereby allowing more of the agent to remain available for therapeutic treatment of the tooth surface.
It is a further object of this invention to provide a preferred dentifrice containing the cationic polymer coated abrasive and a cationic therapeutic agent.